Clingstone peach tree named `Late Ross `

ABSTRACT

A new and distinct cultivar of peach tree (i.e., Prunus persica) is provided that originated as a scaffold mutation of unknown causation of the `Ross` cultivar (U.S. Plant Pat. No. 4,863). The new cultivar forms attractive fruit that is well suited for canning which matures approximately ten days later than that of the parent `Ross` cultivar. Commonly a distinct red stripe is formed on the suture line of the fruit. All other characteristics of the new cultivar are believed to be substantially identical to those of the `Ross` cultivar. The later fruit maturity offers fruit growers and canneries more flexibility in the harvesting and canning of the fruit crop through the simultaneous growing of the `Ross` cultivar and the new cultivar of the present invention without sacrifice of fruit quality.

BACKGROUND OF THE INVENTION

The `Ross` cultivar of clingstone peach is the subject of U.S. PlantPat. No. 4,863. Such cultivar was the product of a breeding programcarried out at the University of California experimental orchard locatedat Davis, Calif. The `Ross` cultivar is recognized to possess manyattractive attributes, such as productivity, regularity of bearing,uniformity of fruit size, and processed fruit quality, and is beinggrown primarily by commercial cling peach growers for canning. Itcurrently is believed to be the most heavily planted canning peach inCalifornia. The harvest period for the `Ross` cultivar is currentlyrecognized to substantially coincide with that of older cling peachcultivars, such as `Carolyn` and `Monaco` (each non-patented in theUnited States). However, these older cultivars are known to commonlyexhibit less desirable fruit production characteristics than the `Ross`cultivar.

SUMMARY OF THE INVENTION

The present invention is directed to a new and distinct peach (i.e.,Prunus persica) cultivar that was discovered during 1994 as a scaffoldmutation of unknown causation of the `Ross` cultivar. The new cultivarwhile propagated on Nemaguard peach rootstock was found within anorchard planted during 1990 at the Kearney Argricultural Center of theUniversity of California located at Parlier, Calif. Such orchard hadbeen planted primarily to investigate the production characteristics ofvarious high density tree training systems.

At the time of discovery a single tree of the `Ross` cultivar was foundto possess a single late maturing scaffold. The fruit on such branch wasobserved to be of considerably less maturity than all other fruit formedon such `Ross` trees. The potential value of such difference in fruitmaturity was recognized and the tree was carefully preserved and thefruit which was recognized to be immature at the time of the `Ross`harvest was left unpicked. The original tree has undergone extensiveobservation and testing in subsequent years. Had the new cultivar of thepresent invention not been discovered and preserved it would have beenlost to mankind.

The new clingstone peach cultivar of the present invention has beenfound to exhibit the following combination of characteristics:

(a) forms attractive fruit that matures approximately ten days laterthan that of the `Ross` cultivar (U.S. Plant Pat. No. 4,863).

(b) forms a distinct red stripe on the suture line of the mature fruit,and

(c) exhibits other characteristics that are believed to be substantiallythe same as those as the `Ross` cultivar.

During 1995 the new cultivar was propagated at Davis, Calif., bygrafting on peach rootstocks of approximately two years of age. Suchpropagation bore fruit during 1996 with the first substantial cropoccuring in 1997 and has been observed to reproduce true to type in allrespects.

Some fruit of the new cultivar from the original scaffold was canned atDavis, Calif., during 1995, and has undergone quality testing. Duringsuch testing canned fruit of the new cultivar was awarded high ratingsas was the fruit of the `Ross` cultivar.

Wood of the new cultivar has been subjected to the virus indexingprogram of Foundation Plant Materials Service, University of Californiaat Davis, Calif. All indices have proven to be negative for viruses.

Since the initial fruit harvest time of the new cultivar generallycoincides with the final harvest time for the parent `Ross` culivar, itis now possible to provide canneries with a continued supply of highquality peaches over an additional two to three week period of thegrowing season. The canning sequence made possible by the older `Ross`cultivar and the mutation of the present invention offers fruit growersand canneries more flexibility in the harvesting and canning of thefruit crop through the use of both the old cultivar and the new cultivarwithout sacrifice in fruit quality. Accordingly, existing cannerieslocated near the growing areas where the `Ross` cultivar is grownconveniently can process the new cultivar without the need for anysubstantial additional capital expenditure.

The new cultivar of the present invention has been named `Late Ross`.

BRIEF DESCRIPTION OF THE PHOTOGRAPH

The accompanying photograph shows specimens of the foliage and fruit ofthe new cultivar as depicted in color as nearly true as it is possibleto make the same in a color illustration of this character. The tree ofthe new cultivar was grown at the Kearney Agricultural Center of theUniversity of California located at Parlier, Calif. The fruit was nearfull commercial maturity.

DETAILED DESCRIPTION

The following is a detailed description of the new cultivar obtainedfrom the original scaffold mutation and its progeny during the 1997growing season. The trees were grown at the Kearney Agricultural Centerof the University of California located at Parlier, Calif. Colordesignations are presented with reference to the "Dictionary of Color"by Maerz and Paul, First Edition (1930).

Botanical classification: Prunus persica, cv. `Late Ross`.

Tree:

Size.--Medium. The trees resulting from the asexual propagation of 1995during the fall of 1997 had a height of approximately 3.6 meters, abreadth of aproximately 3.7 meters across the crown, and commonlypossessed approximately five scaffolds.

Vigor.--Medium. Produced approximately 0.77 to 0.91 meter of new growthduring the 1997 growing season.

Growth.--Upright to upright-spreading.

Hardiness.--Hardy under typical San Joaquin Valley climatic conditions.

Production.--Productive.

Bearing.--Regular bearer.

Trunk:

Size.--Medium to large. The trunk diameter of the original tree at 10cm. above the ground is approximately 22 to 24 cm. The scaffolddiameters at the base of the scaffolds are approximately 12 cm. andthose of the parent `Ross` cultivar are approximately 10.8 to 11 cm.

Texture.--Relatively coarse with substantial scarfskin.

Color.--The bark color ranges from brown-grey (15-C-8 Chukker Brown) tomore medium brown (8-J-10 Falcon Brown).

Lenticels.--Numerous, large, flattened and generally oval-shaped.Typically the lenticels range from approximately 2 to 7 mm. in width ata right angle to the trunk and are approximately 1 to 3 mm. in height.The lenticel surface is light brown in coloration (13-H-8 Bure Brown)and is somewhat calloused.

Branches:

Size.--Medium.

Texture.--Medium.

Color.--Mature shoots are light brown (14-1-8Madura Brown) to darkerbrown (7-E-11 Trotteur Tan). The current season's shoots are pale lightgreen (18-1-5 Sky Green). The exposed surfaces are commonly tingedrose-red (5-J-9 Bois de Rose). The coloration of the new expanding shoottips is bright yellow green (17-L-4).

Lenticels.--Somewhat linear at a right angle to the shoots, and light incoloration.

Internode length.--On current season's hanger shoots the length betweennodes commonly is approximately 10 to 25 mm.

Leaves:

Size.--Medium to large. Typical length from vigorous current season'sgrowth is approximately 15.7 to 17.7 cm. including the petiole, andtypical width is approximately 3.9 to 4.6 cm. The leaf thickness isaverage.

Form.--Lanceolate.

Apex.--Acuminate and often curves downward and is twisted sideways.

Aspect.--The blade commonly ranges from substantially flat to somewhatfolded upwards.

Color.--The upper surface is dark green (23-J-6) and the lower surfaceis a much lighter grey-green (21-H-6). The primary and mid-vein on theunder surface is pale yellow-green (17-J-3).

Margin.--Crenate and occasionally double crenate. The crenations arerelatively large and uniform. The leaf margins commonly range fromstraight to moderately undulate.

Petiole.--Generally medium in size, commonly approximately 8 to 10 mm.in length, approximately 2 mm. in thickness, and pale yellow-green incoloration (17-H-4).

Glands.--Small to medium in size, almost always globose, alternate,commonly 1 to 2 on the petiole, often borne on a short stalk, andfrequently 0 to 2 additional glands can be observed at the base of theleaf blade. The coloration is shiny light green-yellow (17-K-5) andoften with a reddish center.

Stipules.--Linear lanceolate in configuration, most are early deciduous,margins are serrate, commonly approximately 6 to 9 mm. in length, andthe coloration of young stipules commonly is light green-yellow (17-K-5)with darkening to brownish upon aging.

Fruit:

Maturity when described.--Full commercial maturity.

Picking.--First pick was Aug. 1, 1997 and last pick was Aug. 6, 1997.

Season of maturity.--Approximately ten days later than the `Ross`cultivar (U.S. Plant Pat. No. 4,863).

Size.--Uniform, large. Average axial diameter is approximately 61 to 67mm., the average suture diameter is approximately 64 to 71 mm., and theaverage cheek diameter is approximately 65 to 72 mm.

Form.--Globose to slightly oblate in lateral aspect, and in the apicalaspect varies from globose to slightly oval with a slight elongation ofthe ventral suture area. Most frequently the fruit is slightlyasymmetrical.

Suture.--Clearly evident and extends from the fruit base to the apex.Overall the suture is quite shallow, but sometimes deepens within thestem basin and is slightly depressed at the apical end. A slight amountof stitching sometimes is present. The width commonly ranges from 1 to 4mm. The suture line characteristically is light red (5-K-10 Ember Red)to a darker red (6-L-11 Egyptian Red). Such a distinct red stripe on thesuture commonly is absent on the fruit of the parent `Ross` cultivar andsometimes is there replaced by a red blush at the area of the suture.

Ventral surface.--Relatively smooth and only occasionally lipped.

Base.--Commonly varies from round to slightly truncate. The base anglecommonly is also visible and most frequently is at a right angle to thefruit axis, but occasionally is slightly oblique to the fruit axis.

Stem cavity.--Oval, relatively small, commonly approximately 26 to 32mm. in length, approximately 20 to 29 mm. in width, and approximately 12to 14 mm. in depth. Some depressions may be present in the cavityshoulder where the fruit was pressed next to a bearing fruit shoot.

Apex.--Commonly rounded with a depressed tip.

Pistil point.--Most frequently is oblique.

Stem length.--Commonly approximately 5 to 6 mm.

Stem thickness.--Commonly approximately 3 to 3.5 mm. and usually morethickened at the distal end.

Stem color.--Light greenish-yellow (12-L-3 Pyrite Yellow) to slightlymore yellowish (11-L-2 Pyrethrum Yellow).

Skin pubescence.--Lightly to moderately pubescent, with short, finegreyish pubescence.

Skin flavor.--Relatively neutral.

Skin tenacity.--Tightly attached to the flesh at commercial maturity.

Skin tendency to split.--None observed.

Skin color.--A mix of yellow ground color and a red blush with adistinctive red suture line. The red blush can vary from approximately10 to 50 percent of the skin surface. The blush form includes bothwashed and striped patterns. The blush coloration commonly ranges frommedium red (5-H-10 Rosewood) to dark red (6-L-12 Indian Red) withdegrees of shading in between. The red suture line ranges from light red(5-K-10 Ember Red) a darker red (6-L-11 Egyptian Red). The washed areasof red color can be somewhat dappled and speckled in appearance. Theground color ranges from light yellow (9-K-3 Empire Yellow) to a moregolden yellow (9-L-6 Golden Glow). The ground color commonly coversapproximately 50 to 90 percent of the fruit surface.

Flesh color.--Very uniform yellow from skin to stone (9-L-5). A very fewshort whitish fibers occasionally are present. No red coloration ispresent under the skin or next to the stone at commercial maturity.

Flesh texture.--Firm, very fine textured, and non-melting.

Ripening.--Ripens evenly.

Flavor.--Very pleasant, mild and well balanced.

Aroma.--Pleasant and moderate.

Eating quality.--Good.

Canning quality.--Very good.

Stone type.--Clingstone with flesh connected over the entire stonesurface.

Stone size.--Medium and commonly ranges from approximately 34 to 38 mm.in length, approximately 25 to 28 mm. in width, and approximately 17 to22 mm. in thickiness.

Stone form.--Sightly obovate and at times approaching oval.

Stone base.--Slightly oblique to the stone axis.

Stone hilum.--Relatively large and well defined, oval, with a thickenedcollar, substantially grooved, and present surrounding the hilum scar.

Stone apex.--Generally rounded with a short tip.

Stone sides.--Somewhat variable, ranging from equal to very slightlyunequal.

Stone surface.--Pitted and grooved with the pitting being most distinctover the mid-stone surfaces laterally, and the grooves most distinctnear the stone base and along the ventral edge.

Ventral surface.--Relatively narrow, commonly from 5 to 6 mm. in widthat mid-suture. Low wings commonly are present along the entire ventraledge with substantial erosion of the wings over the basal shoulder tothe base.

Dorsal edge.--Relatively prominent, and deeply grooved from the base towithin approximately 5 to 10 mm. of the apex. The apical shoulder issubstantially eroded, especially in near proximity to the apex. Theridges subtending the dorsal groove are high and occasionally cross-cutwith grooves.

Stone color.--When dry, light tan-brown (14-D-9).

Tendency to split.--None observed.

Flowers:

Chilling season.--Low to medium for growing location. There wereapproximately 827 chilling hours below 45° F. for the 1996--1997 winterseason.

Buds.--Medium to large in size, conic in form, plump, slightly appressedto the bearing shoot, and bear pubescent surfaces of a light greycoloration. The exterior bud scale ranges from grey (15-A-6 Beaver Grey)to grey-brown (15-A-8 Winter Leaf Brown) in coloration. The buds arehardy under typical climatic conditions of the San Joaquin Valley. Therecommonly are one to two floral buds per node and most frequently twofloral buds per node.

Bloom timing.--Early to midseason in relation to other commercial clingpeach cultivars. During 1997 was approximately two days after the parent`Ross` cultivar. More specifically, the date of the first bloom was Feb.18^(th) and the date of full bloom was Mar. 5^(th). In comparison, the`Ross` cultivar exhibited a date of first bloom of Feb. 16^(th) and adate of full bloom of Mar. 3^(rd).

Size.--The flower size is large and showy. The fully expanded flowerdiameter commonly is approximately 28 to 40 mm.

Bloom quality.--Commonly abundant throughout the tree.

Petals.--The petal size is large and commonly ranges from approximately17 to 21 mm. in length and from approximately 17 to 20 mm. in width. Thepetal number is five. The petal form varies from broadly ovate to attimes nearly oval. The young petals are light pink (1-C-7 Pink #2) anddarken slightly at maturity to (1-E-2). The petal claw is moderatelylarge and truncate in form. The claw color is dark rose-pink (1-J-4 RoseNeyron) and darker than the overall petal. The petal margins vary frommoderatly smooth to somewhat ruffled. The petal apices are variable,most frequently rounded and are somewhat raised at times.

Pedicel.--Quite short and commonly exhibits a length of approximately 1to 1.5 mm. and a thickness of approximately 1 to 1.5 mm. The colorationis bright green (17-L-6) and the surface is glabrous.

Nectaries.--Bright orange (9-C-11) and becoming slightly darker atmaturity.

Calyx.--Glabrous and quite rugose, and the coloration is light maroon(5-J-4) with areas of green (19-L-2) Jewel Green) especially basally,and darkening to intense maroon (6-J-5) Rubaiyat).

Sepals.--Highly pubescent with long greyish pubescence, average in size,conic in form, and dark maroon (6-J-4 to 6-J-5) in coloration.

Anthers.--Average in size, dark red dorsally (5-L-11 Brickdust) andtan-red ventrally (4-A-10 Woodland Rose) with red streaking (5-K-9Rosevale Red) on each side of the filament attachment.

Stamens.--Varible in length and commonly range from approximately 11 to15 mm. in length. Frequently extend well above the pistil. The filamentsare very pale pink when young (1-C-1) and become dark maroon (3-J-5)with advancing maturity.

Pollen.--Abundant yellow-gold (10-K-5) in coloration.

Pistil.--Very pubescent basally over the ovary, and less so near thestigma and over the upper style area. The length commonly isapproximately 12 to 15 mm. including the ovary. The coloration basallyis pale green (17-J-3) and a paler green (17-J-1) over the upper stylearea.

Major use: Canning.

Keeping quality: Good.

Resistance to insects and diseases: Average.

We claim:
 1. A new and distinct cultivar of peach tree exhibiting thefollowing combination of characteristics:(a) forms attractive fruit thatmatures approximately ten days later than that of the `Ross` cultivar(U.S. Plant Pat. No. 4,863), (b) forms a distinct red stripe on thesuture line of the mature fruit, and (c) exhibits other characteristicsthat are believed to be substantially the same as those as the `Ross`cultivar;